public async static Task <MCTSNode> ProcessTree(MCTSNode aRootNode, IGameState aGameState, MCTSConfig aConfig)
{
bool verbose = aConfig.Verbose;
Action <string> printfn = aConfig.PrintFn;
uint maxIters = aConfig.MaxIterations;
MCTSNode root = aRootNode;
bool done = false;
int iters = 0;
do
{
MCTSNode node = root;
// Select
while (node.IsFullyExpandedAndNonterminal)
{
node = node.SelectChildByPolicy();
}
// Expand
IAction newAction = node.GetRandomUntriedAction();
if (newAction != null)
{
IGameState state = newAction.DoAction();
System.Func <MCTSNode> nodeConst = node.GenerateChildFunction(newAction, state);
node = node.AddChild(nodeConst);
}
// getting state reference for Rollout and Backprop
IGameState finalState = node.NodeState.Clone() as IGameState;
// Rollout
finalState = await finalState.SimulateToTerminal();
// Backpropagate
while (node != null)
{
node.UpdateResult(
finalState.GetResult(
node.ActorJustActed
)
);
node = node.Parent;
}
if (++iters >= maxIters)
{
done = true;
}
}while (!done);
MCTSNode bestChild = root.GetBestChild();
if (verbose)
{
printfn(root.DisplayTree(0));
printfn(root.DisplayMostVisistedChild());
}
return(bestChild);
}
public async static Task <IAction> GetAction(MCTSNode aRootNode, IGameState aGameState, MCTSConfig aConfig)
{
MCTSNode processedTree = await ProcessTree(aRootNode, aGameState, aConfig);
return(processedTree.IncomingAction);
}